Internal-combustion engine



FebQ25, 1930. c. s. BARRELL INTERNAL COMBUSTION ,ENGINE 3 Sheets-Sheet 1Filed oct. 28, 1925 /N VEA/TOR# v ATTORNE Y Feb. 25, 1930.-

C. S. BARRELL NTENAL COMBSTION ENGINE Filed Oct. 28. 1925 3 Sheets-Sheet2 A TToR/VEY Feb. 25, 1930. C, s, BARRELL v 1,748,273

INTERNAL COMBUSTION ENGINE Filed OCT.. 28, 1925 l 3 Sheets-Sheet 3lAlean-mai Per. 25,1930 i PATENT vorf-rick:

rCHARLES S. BARRELL, OFFB'OSTON, MASSACHUSETTS INTERNAL-COMBUSTIONyIElll'GfIll':El

Original application led y'The invention to be hereinafter described ilrelates to internal ,combustion engines, yand more.. particularly tosuch engines of the two- `cycle type.. v ,v-

Ithas been proposed to construct an engine Vof this type .comprising acylinder containing fjcam on said shaft.

'primary and `secondary pistons. The pri-y mary piston isconnected by arod and crank ywith the shaft of the engine, and the sec0nd- 2li-ypiston is operatively connected with a i The construction is 'such thaton them-stroke of the secondary piston, thefuel charge is vdrawn intotheY space in the cylinder between the secondary piston and the head ofthe cylinder, and on the ,outstroke thereof, the charge is transferredto the space between 'the pistons, where'it is compressed scavenge outthe burnt vgases from the cylinder through the exhaustport., Y

engine ashitherto designed'. Among others,

' L,the `force of the explosion of the fuel'charge react-ing on thesecondarypiston has 'been transmitted to 4'the actuating cam therefor,

thereby producing objectionable friction,

necting y the same with the 'secondary' piston. One o the purposesv ofthe present invention,

explosion of the fuel charge, the construction being such vthat thesecondary piston Aengages lthe cylinder head uniformly, and the pressureof the explosion is desirably distributed by vthe secondary piston tothecylinder'head,

. and the, Cain and theparts connecting the same l Ithasibenproposed toprovide withl the secondary piston are relieved from thc'sjhocl of theexplosion.

valves in l vthe secondary piston through which'the fuel charge ydrawninto the cylinder by said piston be transferred to thespace betweenl theI-pistpnsv Since these valves are necessarily boni-aed-andpermit more orless leakage from flee. erasebetventhe pistons t0 the'seae bel osed -tothe products 'of combustion of the rv,fuelcharge, they are liable tobecome car- Aug'ust 21, 1919,` serial No. 318,861, Paten-t No.1,710,083. Divided and this application iiled October 28, 1925. SerialNo. 65,327. n

tween the secondary piston and the head of the cylinder, and thencethrough the opening in the cylinder head through which the stern for thesecondary piston projects.` Another object of the invention'is toprovide ymeans for preventing leakage along the stern of the piston.

Another object of the invention is to provide an engine having aplurality of cylinders with the secondary'pistons thereof connected withand actuated by the same cam, thereby A y l der two-cycle yengineembodying the inven- There are certain objections to this type of tion;

for actuating the secondary piston;

Fig. 3 on an enlarged scale is a vertical section through one of thecylinders of the engine; {sho/ck and Wear on the cam andthe parts con- YFig. 4 on an enlarged scale is avertical'sec- 7 tion through a portionof one of the cylinders;

vvtherefore,isto provide a suitable backing or i 'Snpport forthefsecondary piston during the l vsupporting the engine on .the chassislo f an automobile orother support. ,Since these cylinders or units aresimilar, a description kof one will suffice for both.

The c linder 1, for example, maybe provided with a head 9 (Figs and l)detachably secured thereto by screw bolts 11, v.the

walls of the cylindeij and head being formed Fig. 2 is a sider elevationof one of the cams Y The cylinder also 4cor'itains a secondary piston 23in the rpresent instance, formed'of two parts and 27 secured together bycylinder. 'The fuel may screws 29. The outer part of thefpistonmay havea flange 31 adapted co/project into an annular recess 33 formed inthehead ofthe be conductedfrom the carburetor 35 (Fig. 1) through anintake pipe 37 communicating with the port 39 in the cyl-y Vinder,'sa1dport being provided with a springpressed puppetvalve 41.

Theintake valve is located in the cylinder adjacentthefhe'ad thereof ina position such that it is covered by vthe secondary piston when thelatter is in its outermost position.

To prevent leakage of the gases of combustion Vfrom the space betweenthe pistons outward along the inner wall` of the'cylinder to ythekinletvalve and to the carburetor, the

secondary piston may be provided with suitv able'leak-preventingme`ans,'such, for example, asl packing rings 43 which will be atopposite sides of the inlet valve when the secondary piston is in'itsoutermost position, as willbe noted inFig. 3.

yOn'the in-stroke of the secondary piston,

a fuel'charg'e will be drawn from the carbu- ,Y

retor past the inlet valve into the space bef ltween thes'econdarypiston and the head of the cylinder. On the outward stroke of thesecondary piston the fuelcharge thus drawn in, is transferred tothespace between the pistons. lSuitable means may be provided for thispurpose, in the present instanceof the' linvention, inthe form ofaplurality of springpressed puppet valves'45 mounted in and carriedbythe secondary piston, the construction being such that these valves willautomatically remain on their seats on the in-stroke of the secondarypiston, but will move from'their seats on' theQout-stroke thereof toallow the fuel charge to pass into the space between the pistons. I

' Next will be described means for actuating lthe secondary piston., Inthe present in-` stance, t'his means comprisesga stem' 47 'having oneendv thereof suitably connected to the secondary piston,` this,vconnection beingprefera'bly by a universal joint which may be in theform of a ball 49 seated in a socket vformed in the parts 25 and-27` ofthe secondary piston.l 1 The stem 47 projects outward through the yheadvof the cylinder, a suitable,stuffingl boX 51 'being provided v.toprevent leakage i'rointhe,cylinder `along the stem. Adja-V lcentYK theouter end of thestem is across bar v or member53 connected to the outerends of rods .5 5/wh'ich pass inwardthrough suitable guides 57 and 594projecting laterally from j said piston.

the head andcylinde'r. The inner ends of the rods may be provided ywithstuds hav- Y ing rollers 61 working in camways 63 ina cam 65. In thepresent instance of the invention, each cam comprises two'y parts 67andV 69 detachab-ly secured together bybolts 71, and having bosses .73fast on the crank shaft 19, referred to; j

The construction is such that opposed camways are provided inthe partsof the cam -adaptedto receive the rollers on the opposite ends of thestuds carried bythe rods 55, and the latter'project through spaces 75between the cam parts. V As a consequence, a strong cam construction isprovided for efficiently reciprocating the secondary piston. The camwaycomprisesa portion 77 (Fig.

2) of uniform radius extending vnearly through an arc of 180, a. portion79 of varyn 81 for rapidly yproducing the out-stroke of T The portion 77meets the portionsV 79 and81 through portions 83 which may be graduallycurved to reduce friction between the rollers and the camway as much.

as possible. It will be notedthat the camway is located eccentricallywith respect to the crank shaft,and therefore, to avoid a greater'massof material at one side of the cam than the other, recesses 85,(Fig. 3)are formed in the cam to produce a balanced conmotion.l

While eachV of the cams, in thepresent instance, is formedcof two partscontainingopstruction which will have a uniform rotary posed camways, itwill beunderstood that 1n j some cases acam maybe provided having a1single camway. Also, .in some'cases a single f mayl be provided for'reciprocating the ysecondary piston if desired, instead of cams" at theopposite herein# fis-stated, an important'feature of theinsides ofthe'cylin'der as shownA 'Avention consists in means forrelievingthecamjcreams from the shockduetoy the reactive forceof the explosion onthel secondary piston.I 'To accomplishthis, inthev present instance,"the Vsecondary. 'piston is .caused to engage thehead of the cylinderduring theexf plosion ofthe fuel charge,"so that the reactive force willbe transmitted Vfrom the secondary pistonto the 4head of thecylinderinstead'ofto the cam or 'cams through the conncctions between thevlatterand the second- Y. ary piston.Y The'secondaryy piston will engage theVhead of the cylinder while the cam follower rollers Glare working inthe portion 77 of the camway having a'uniform radius. Y It is desirableto provide kadjustable means' in the connections between the cams andthesecondary 'piston in order that theY latter may seat properly againstthecylinder head when the secondary piston is at the L4outward limitv ofits stroke without Strain ongerinjury to' tithei connections vbetweenthe cams and the secondary piston. VTo accomplish this, 1n the presentinstanceoftheinvention, the piston y stem/17 has'a portion projectingthrough the A'.barti, :and nuts 94 are threaded on thefstemandfengageopposite sides of the bar. Thesel `1futsfmay be adjustedtovary' the elicctive Y. length of the -piston stem as' required'.

y Insonieinstances it `may be desirableto prov1o e tonas .itl'approachesvthe head of the cylinder.

f' 'For thispur-pose, in the present form of the "invention,acoilspring95 is provided mounted in `an annular `recess 97 in the cylinder head'thiefinnerA end of said spring being suitably f anchored in saidrecess, and' the'outer end of said sprin-g'beingprovided with a cap 99for videfrneans for cushioning the secondary pis-r engagementwit-h thesecondary piston.V

'- Next will be described 'means for prevent- *l [inglossof power fromtheexploslons 1n case thefvalveslt in thefsecondary piston becomecarbonized andleak.y This means, 1n the present instance, comprlsesaconlcal proJectlon 1 -,01 on thejsecondary piston-adapted totightlyseatagainst a conicalfrecessl in the cylinderhead, the angleofsaidprojection and i recess being of suliicient degree to insure tightengagement 'thereof' without wedging of the projection 4insaid recess soas to interfere f lwithready movementr ofthe Vpiston away -from thehead. The seal thus provided is lo-r cated .between the valvesl Vandthepiston stem 47.k vAs a consequnece, any leakage past lsaidvvalves willbei unable to escape toand lalong said stem. To further contribute tothe prevention ofthe leakage referred to, the pisf ton and cylinder headmay be provided with a i conical projection 105 and a 'conicalrecess107y e *though this second pensable. f

similar to the project-ion and recess described,

- and located radially inwardtl1erefrom,.al

sealing means 1s not 1nd1s l`offurther contributeto prevent-ion ofleakageythe secondary piston may be provided vwithtupstanding circularseats or rings 109.

f (Figs. and 6) on its upper surface surrounding the valve ports andadaptedto engage similar seatsor rings 111 (Fig. 4) on theinner'surfac'eof the cylinder head. Preferably threevalves are employed inthesecondary piston, ands'ince each valve is provided with rings asdescribed, the sccondaryjpiston will seat against thecylinder headatthreepoints.

` This will tend to insure tight engagement 'of' "all three rings of thepiston with all three y -ringsof the cylinder head. Tofurther preventany possibilityof such leakage, the piston may be vprovided with anupstalnding ring f 2113 at they upper surface thereofy encirclingVv fand outside 'ofthe-three rings for the valve ports, and adapted toengage asimilar ring 11,5 on the inner face of the cylinder head en-ylcirclingalltliree rings on the cylinder l1ead. important thatgonexplosion of the fch'arge'betweenthe pistons there should be no ball onthe end of the stem.

Vbackfiresueh as might ignite the fresh kfuel 'charge dra-wn ink by thesecondary piston between the latter and the cylinder head. Suitablemeans may be provided to prevent such @,occurirence, andin the presentinstance, each oft-hevalve ports may be covered by a gauze y, diaphragm11.7r 1g. '5) suitably secured to thepiston. 7

Toffacilitate removal of carbon deposits on the inner faces of thepistonstwo diametri.-

ycall "opposed eXhaustwJorts 121 Fim-1. ma

y l e Y be employechthe construction being such that the pipeconnections 123 lfor the exhaust ports may be` removed, and then one canlook through one of'theexhaust por-ts while a tool is inserted throughthe opposite exhaust port and mainpulated to scrape the carbon from thepistons.

After the explosion of a chargebetween thevpistons, thesecondary pistonis moved kquickly downwardto scavenge or drive out to allow escape ofthe burnt gases,fand then fresh air may be drawn in through the air portby the vacuum and follow the burnt gases out through the exhaustport,*thereby 'insuring the complete discharge of all burnt gases. Thentheprimary piston moves up- `ward,'it will iirstclose the air port andthen close the exhaust' ports. LThe secondary piston, however, is movedupwardly more rapidly than the primary piston, so that thefresh chargewill be transferred from the space between thesecondary piston and thecylinder head' into the space between the two pistons, and this-,freshcharge will n ot be adultera'ted by anyresidual burnt gasesin the space'between the pistons.

` To provide lubricant for the stem of the secondary piston, a greasecup 127 may be ymounted on the cylinder head and feed lubricant to ltheportion of the stem which reci vrocates thi-ough the head. Thislubricant may Agravitate downward along the stern toward the ball of theuniversalfjoint'at the lower end of the stem. Thepiston may have a.circu lai` groove 129`adjacent the stelnto catch lubricantand guide'thesame inward nward the A spark plug 131 (Figs. l andV 3) may tons.` l

As sl1ownhere1n,ftwo cylinders are provided, disposed ata V-angle, andone caln may Serve both cylinders, sincey a plurality of followersworlron the same cam and have yconnectlons leadlngtherefrom to theseeondn be connectedto the cylinder'a-t a point to ignite `thecompressed fuel charge between the pisp i' i aryipistonsof thecylinders.: While two cyl-v quickly back toward said head. The radii ofprogressive points of the camway for moving said piston downand uprapidly, vary considerably in length untilithe piston almost reaches thehead of the cylinder, and is, for example, about one-half inch from saidhead. The radii of progressive' points on the camway in moving thepiston through this final one-half inch distance, vary but slightly. Asa consequence, the piston is slowlymoved by the cam through thisl lastone-half inch distance to thehead vof the cylinder, and poundf ing ofthe piston against the head of the cylinder is prevented. The piston isthus seated against the head of the cylinder, and the reactive force`of-the explosion is borne V.by the head of the cylinder rather than theconnections between the'secondary piston and the actuating camtherefor.I

In operatiomthe secondary piston will `be ymoved downward to draw 'afuel charge'y through the inlet port .into thes'pace betweenthesecondary piston and the cylinder head, and in the course of thismovement will scavi enge out the burnt gases resulting from the previousexplosion. s Then the secondary piston ,will move upward and force thefuel charge thus drawnl in past the 'valves 45 into the space betweenthe pistons.- The primaryv piston will follow-the secondary piston inits Y upward movement and compress the fuelV charge between them, saidcharge'being then ignited, and causing thefpower stroke of the primarypiston. During the explosion of the charge the secondary piston willremain seat` ed againstY the headof the cylinder, so that the reactiveforce of the explosion will be -transmitted from the secondary piston tothe cylinder head,and not to the actuating cam therefor.

It will be understood ythat the invention is A. not limited tothespecific embodiment shown, y

and that various `deviations may be made l f therefrom without departingfrom the spirit and scope of the vappended claims.

The present' applicationV is a divisionfrom my'copendingapplicationSerial No. 318,861, Yfiled August 21, 1919. f 1 y .1i A two-cyclevinternal combustion engine,

comprising, in combinatioma cylinder, primary and secondary pistonstherein, a ystem connected to said secondary piston extending.

through the cylinder head, and valvemeans for transferring the fuelcharge from achamf ber at one side ofsaid secondary piston to theoppositelside thereof','said secondary piston and the head of thecylinder having provision' for inter-engagement to prevent leakage fromsaid valve means along said stem during explosion of the fuel charge.

2. A two-cycle internal combustion engine, :comprising,'in combination,a cylinder, prif mary and secondary pistons therein, a stem connected tosaid secondary-piston extending said stem, valve means' forVtransferring the fuel charge froma chamber at one side of the throughthe cylinder head, a stuffing boxfor Y' i' secondary piston to theopposite side there- 1 of, and vmeans positioned bythesecondary pistonto prevent leakage along the stem and 'throughv said stuffing box duringexplosion of the fuel charge. l

3. A two-'cycle internal combustion engine,

comprising,in combination, a cylinder, primary and secondary pistonstherein, a stem connected to said secondary piston extending through thecylinder head, valvemeans on said secondary piston for transferring'`the fuel charge kfrom one Vside ofsaid secondary piston to the otherside thereof,and seats on j said secondary piston and cylinder headyinterposed between said valve means and piston stem to'prevent anyloss:A of kcompression or fluid leakage through said valvejmeans and Yalong said stem. f, .i i

Y 4. two-cycle internal combustion engine, f

comprising, in combination, a cylinder havn` l ing` a head, primary andsecondary pistons, a shaft rotated by said primary piston, cam

means driven by said shaft, connecting meansbetween said cani means andsecondary piston to reciprocate the latter Ttoward and awayv from saidhead, and means be-V l tweenthe head ofk the cylinder and thesecondarypiston.V forcushioning the latteron its/movement towardY the'limit ofits' outward stroke. Y

5. A two-cycle internal combustion engine,`

comprising, vin combination, aV cylinder -hay7` ing a closed head,primary andv secondary pistons in the cylinder, valve ports in .saidsecondary piston to admit .fuel charges from g the space between thesecondary-piston and on the secondary piston forengagement with kpartsof saidhead to prevent leakagebe. tween them.V f

6. A two-cycleinternal combustion engine,

Ythe'cylin'der head to the. space between the i pistons, anda membersurroundingeach port comprising, in combination, a cylinder, priv `maryand secondary pistons therein, va stem Uh for said secondary pistonprojecting throu.,D

the cylinder head, and having aball seatedVV v1n a socket inthesecondarypiston, and

lubricant supply means'to admit lubricant to said stem and along thelatterto said ball l and socket.

7. two-cycle internal combustion engine,

comprising, in combination, a-tcylinder having va closed head, primar-yand 'secondary pistons in said cylinder, a shaft rotatedby pistonstherein, afstein connected to the secmeaprmary piston, meansfoperated bysaid 'shaft for reciprocating` the secondary piston toward and away fromsaidhead, and spring means between thehead ofthe' cylinder and thesecondary piston' forcushioning the latoutwardy stroke.

ter' on its movement towardsthe limit ofk its 8. A two-cycleinternalcombustion engine,

comprising, 'in combination, a cylinder having a closed head, primaryand secondary ondary piston extending through the cylin-y der head,means cooperating'with said stein for/'reciprocating the secondarypiston toward and Aaway from the head, and valve means for transferringthe fuel charge from one side thereof to the other, said ysecondarypistonand the head of the. cylinder being providedvwitli intersengagingtapered seats to preventleakage ofthe gases from the combustion` chamberto said stem during explo sionv of the lfuel charge. v`

QJ-A'twocycle internal combustion engine, comprisingn combination, acylinder having fa hea' d ,f primary and secondaryfpistons in;saidfcylinder, a shaft rotated' ,bythe pri- 5 mary'piston, a groovedycamsecured tosaid shaft, 7a follower slidably engagingthe cam followertoreciprocatethe secondary piston,

f through substantially a semi-circle, a portion of; varying radius, andvoppositely disposed ygradually rounded lportions connectingthe groove,a "stem connectedV to the secondary piston, andmeans connected to saidstemand said cam groove having a portion of uniform and relatively largeradiusI extending portions of uniformand varying radius, one of'saidpoi-tioiisca-usingthesecoiidary piston gine, comprising, iincombination, a cylinder,

piston andfhaving a balljeiid connedby gradually` to Qapproachandseat'against the Y head lof the cyindfer, v

:10,A two-cycle vinternal combustion en` a primary piston therein, asecondary piston therein formedof two parts secured-together andhaviiigra ball socket therebetween', a stein for imparting movement tothe secondary saidparts within'- said socket, and means Vfor'.@impartingmovement toysaid stem.

A tW'o'cycle .internal combustion engine,.compri sing, incombination, acylinder, a priniaiypiston therein, asecondary piston therein'comprisingapairof heads secured togetherandihaving a ball socket between theinavstein for imparting iiiovementto' the secondarypis'tonand having arounded head confined 'said heads withinfsaid socket,

'and means fr imparting movement to 'said storm v a y 12."A"two1'cyc1einternal v combustion en# gine, comprising, in combination, a cylinder,

I Y a fp'gtontherein comprisingl a pair `of heads secured 4together/andr having -a ball'socket betweenthern, v'and astem `for said pistonhaving a rounded head confined by said heads within said socket.y

13. A two-cycle internal combustion engine,

comprising, in combination, a cylinder, a primary piston therein, asecondary piston therein formed of two parts secured together andprovided with a socket, a stem for imparting movement to the secondarypiston and having av rounded end confined by said-parts within saidsocket, a crank shaft operatively connected to the primary piston, andmeans for operating the stem from said crank shaft.

14. Atwo=cycle internal combustion engine, comprising, in combination, acylinder, prikmary and secondary lpistons therein, ymeans including astem for impart-ing movement to the secondary piston, and having auniversal joint connection with said secondary piston` to permitthelatter to seat luniformly against the head of the cylinder .when atthe outward limit of its stroke.

l5. A- two-cycle `internal combustion ken-l gine, comprising, incombination, acyl'inder,

primary and secondary pistons therein, and means for reciprocating thesecondary piston includingla stem having a terminal ball, said secondarypiston being provided with a socket to receive said ball to enable thesecondary piston to seat uniformly'against the head of' the Ycylinderwhenat the outward limit'of its stroke. 4 e

116. A Ytwo-cycle internal combustion engine, comprising, incombination, a cylinder,

primary and secondary pistons therein, and

sioii for moving thesecondary piston into en` gagement'with the cylinderhead, means for transferring the fuel charge from the space between thesecondary piston and the cylinder khead to thespacebetwecn the pistons,said secondary vpiston'an'd cylinder headhaving provision enabling thesecondary piston to yseat uniformly against the head, thereby to preventstrains tending to destroy aizialaline-y ment ofthe secondary pistonwith respect to the cylinder on explosionof the fuel charges.

18. A two-cycle internal combustion lengine', comprising, inkcombination, a cylinder,

vprimary and secondary pistons therein, means for reciprocating thesecondary piston including a stem connected tothe secondary piston andprojectingthrough the cylinder head, yand means for transferring thefuel charge from thefspace between the secondary piston and lthecylinder headjto the space between 1the pistons, said secondary pistonandthe cylinder head being constructed and arranged for the secondarypiston to vseat against the cylinder headand prevent leakage of thegases of explosion from the cylinder through thei opening of thecylinder lhead receiving the stem. Y

c 19. A two-cycle internal combustion engine, comprising, incombination, a cylinder,

primary and secondary pistons therein, andy means for reciprocating thesecondary piston` including a stem connected tol the secondary pistonand projecting through the cylinder head, and meansfor transferring thefuel charge from the space `between the secondarypiston-.and thecylinder head to the space between the pistons, said secondarypiston andhead'having portions constructed and arrangedfor engagement to preventleakage from the cylinderk through the'opening in the cylinder headreceiving the piston stem. y

20. Aj two-cycle internal combustion engine, comprising, incombination,a `cylinder having a head, primary and secondary pistons in saidcylinder, a shaft, a crank on said shaft,

a rod connecting saidcrank Vto the primary piston, a cam rotated by saidshaft having afgroove therein, and connections between the camgroove andsecondary piston, said groove having a portion of uniform and relativelylarge radius, a portion ofA varying radius and tions ofuniform andvarying radius, one of:

gradually curved portions connecting the porsaid portions for causingthe secondary pistony gradually toy ,approachl and seat againstk thecylinder headA withoutpounding the same.

' 21. A.two-cycle internal combustion en-` gine, comprising, incombinatioma cylinder fhaving a head, primary and'secondary pistons insaid cylinder, means forreciprocatingthe `secondary piston including acam having a follower, a member connected to said follow,- er, a stemconnected to the secondary piston, and means connecting said member andstem having provision relatively to adjust the same to enable thecam toseat thev secondary piston against the cylinder headwith'out poundingthe same. i v

'22. A two-cycle internal Vcombustion engine, comprising, incombination` a cylinder Y havinga head, primary and secondary pistons insaid'cylinder, and means for imparting reciprocatory. movements to thesecondary piston including a cam, 'a follower, andconnections betweenthe follower and secondary kpiston having meansfor adjusting theeffective length of theconnections in order that the secondary pist-onmay seat against the head of the cylinder when` at the outward limit ofits stroke. v f f 23. A two-cycle internal combustiony engine,comprising, in combination, a cylinder,

primary and secondary pistons therein,

means for reciprocating the secondary piston, and means fortransferringl a fuel charge from the `'space between the secondaryVpis-V ton and the cylinderhead tothe space between the pistons, saidymeans for reciprocating the Y secondary piston having provisionjformoving the` secondary piston into engagement with the cylinder headwithout pounding the of the secondary piston. 24. A two-cycle internalcombustion engine, comprising, in combination, a cylinder same when atthe outward limit of the stroke having a head, primary and secondarypistons therein,and meansfor reciprocating the 'secondary'pistonincluding a cam and connections having adjustable means forvaryingthe'eifective length tliereof-,`that the secondary piston mayfseatagainst the cylinder head Y when at the outer limit of its stroke. 25. Atwo-cycle internal combustion'engine, comprising, in combination, aplurality of cylinders, leach having a closed head andI primary andsecondary pistons therein, aV

shaft, means connecting the primary pis-- ytons with said shaft, av camdriven by said shaft, and Aconnections vbetweenfthe cam and thesecondary pistons, said cam having a portion of varying radius A.formoving the sec# ,Y ondary pistons-into and outv of engagement with theircylinder headsand av portion of uniformradius V:for causing thei'secondary pistons to seat and dwellfagainst the Vcylinder heads att'heouter limits of vtheir strokes.V

l 26. A`A two-cycle internal combustion en# gine, comprising, incombination, vaipluralityV u of angularly relatedv cylinders,-feachhaving. Y

Va closed head and primary and*secondary` pistons therein, a'shaft',"cranks on said shafts,

rods connecting said cranks with `said pri-Q maryv pistons, a cam drivenlby saidishaft,

yfollowers for said cam, andV members connect- Ylos ing said followerswith the secondary pistons','said cam having aportion of varying I yradius for reciprocatlng thesecondary pis? y,

yton's'and a portion of' uniform radius for l i causing the secondarypistons'toy seat and'v dwell against the cylinder heads when at theVouter limits of their strokes.`

iio

27. A two-cycle internalcombustion en-v iso for causing the secondaryypistons to'dwell t in engagement with the cylinder heads.

28.` A two-cycle internal combustion engine, comprising, incombinatiomafplurality 'Y Y of angularly yrelated cylinders, each havinga closed head andprimaryand secondary l' Y pistons therein, a shaft,cranks on saidy shaft,

Y, y,rods connecting the cranks with the second n ondary pistons, saidcams having portions of varying radius for reciprocating the secondarypistons, cams driven by said shaft, and

connections between said cams and the secary pistons and portionsofuniform radius for' causing the secondary pistons to seat and dwellagainst the cylinder heads when at the outer limits 0f their strokes.

rv.29. 'A i two-cycle internal combustion engine, comprising, incombination, a plurality of angularly related cylinders, each having aclosed head and primary and secondary pistons therein, ka shaft,crankson said shaft, cams driven by said shaft, followers for said cams, stemsconnected to the secondary pistons, bars for said stems, rods connectingthe Y p bars with the cam followers, and guides for said rods'mou'ntedon the cylinders externally thereof, said cams being formed toreciprocate the secondary the cylinder heads. s CHARLES S. BARR-ELL.

pistons to and away fromr

